Dishwasher spraying assembly



May 28, l1968 w. H. sToUDER DISHWASHER SPRAYING ASSEMBLY 2 Sheets-Sheet l Filed Sept. 27, 1955 mman/wwwa May 28, 1968 w. H. sToUDER DISHWASHER SPRAYING ASSEMBLY 2 Sheets-Sheet 2 Filed Sept. 27, 1965 United States Patent O 3,385,523 DISHWASHER SPRAYING ASSEMBLY William H. Stouder, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed Sept. 27, 1965, Ser. No.490,213 9 Claims. (Cl. 239-261) ABSTRACT OF THE DISCLOSURE A dishwasher spraying assembly comprising a rotatable section communicating with a non-rotatable section through a Venturi tube having a converging portion attached to said non-rotatable section and a diverging portion connected to and rotatable with said rotatable section. The converging and diverging portions are separated by a transverse gap at the throat of the Venturi tube for providing a joint between the rotatable and nonrotatable sections permitting free rotation of the rotatable section While effectively eliminating leakage of iluid from said spraying assembly at the gap between the converging and diverging portions because of the reduction in the static fluid pressure in the throat of the Venturi tube.

This invention generally relates to apparatus for washing dishes, and more particularly relates to a dishwasher provided with an improved rotatable water spraying assembly.

In current domestic dishwashers, as illustrated in United States Patent 3,090,391, the washing chamber is provided with a rotatable water spraying assembly which discharges fresh or recirculated wash and rinse water against the dishes from many different angles. Such assembly, in current dishwashers, usually comprises a spraying conduit having a stationary lower section connected to a suitable water pump and an aligned rotatable upper section in communication with the lower section through a face-sealed rotation joint or through an arrangement of telescoping or other spaced-apart conduits. By either of these constructions, wash or rinse water pumped under pressure into the lower stationary section ofthe spraying assembly will flow into the rotatable upper section through the rotation joint and will discharge onto the dishes in the wash chamber through suitable reaction jets which are usually provided in outwardly extending spray arms included on this rotatable section. The only means usually employed to rotate this upper section of the spraying assembly within the washing chamber is the reaction force created by the pressurized flow of water through these reaction jets.

A disadvantage of many current dishwashers has been the lack of an adequately designed uid seal for the rotation joint between the stationary and rotating sections of this type of Water spraying assembly. Prior face seals generally have failed to eliminate the undersirable frictional resistance of the joint which inhibits the free rotation of the upper section of the assembly. The telescoping or other spaced-apart joints have previously been unable to prevent a substantial amount of washing or rinsing water from leaking outwardly through the joint into the medium surrounding the spraying assembly.

It is therefore the principal object of this invention to provide a dishwasher including an improved water spraying assembly which reduces or eliminates rictional and fluid losses heretofore occurring during the spraying operation of the dishwasher.

It is a further object of this invention to provide a dishwasher having an improved rotatable water spraying assembly which includes means to eltectively seal the joint between the rotatable and stationary sections of the assembly in a manner which eliminates frictional and iluid losses at the joint.

It is a still further object of this invention to provide a Water spraying assembly for a dishwasher including means which etectively seal the joint between the rotatable and stationary sections of the assembly by substantially eliminating the pressure diierential between the iluid in the interior of the assembly at the joint and the medium surrounding the joint.

Further objects and features of this invention will become apparent from a description of an embodiment thereof, as illustrated in the accompanying drawings. In these drawings:

FIGUR-E l is a front elevational view in partial section of the lower portion of a dishwasherprovided with the water spraying assembly in accordance with this invention;

FIGURE 2 is a right side elevational view in partial section of the dishwasher illustrated in FIGURE l;

FIGURE 3 is an enlarged sectional view taken along the line 3 3 in FIGURE l; and

FIGURE 4 is an enlarged sectional view of the rotation joint of the dishwasher spraying assembly in accordance with this invention.

Referring to these drawings, a dishwasher of the type under consideration is generally indicated by the reference numeral 10. This dishwasher 10 has a support frame 11 which defines a washing compartment or chamber 12, and includes one or more pairs of tracks 13 for supporting racks or baskets designed to receive the dishes or other articles to be washed. This dishwasher 10 also includes a bottom member 20 which encloses the lower end of washing chamber 12.

FIGURE l shows that this bottom member 20 includes a recessed sump well 21, in open communication with the washing chamber 12, which may house a self-cleaning strainer assembly 25 for iiltering the wash and rinse water before recirculation through the dishwasher. As more uly described and claimed in the above-mentioned Patent 3,090,391, this strainer assembly 25 includes a circular screen 26 for filtering soil particles from the water, and a rotating strainer spray arm 27 which dislodges the accumulated soil particles from screen 26 and floats them into a lower trough 22 provided in the sump well 21. A drain pump 23 connected to this trough 22 by means of a conduit 24, as best seen in FIGURE 2, can then discharge the spent Water and entrained soil particles to a suitable drain trap through a drainage loop formed by conduits 28 and 29 (FIGURE l).

This dishwasher apparatus 10 further includes a suitable inlet conduit 30, shown in FIGURE l, for admitting fresh water or air to the washing chamber of the dishwasher, and a circulation pump 35, shown in FIGURE 2, for recirculating the water within the dishwasher vduring the washing and rinsing cycles. FIGURE 2 illustrates that this pump 35 is connected to the sump well 21, preferably at a position below strainer assembly 25, by means of inlet conduit 36 so that the pump may receive the filtered washing or rinsing water accumulated in the sump well. In addition, the discharge end 34 of pump 35 is connected by means of discharge conduit 37 to the lower section 50 of the water spraying assembly 40 of this invention, through an inlet opening 52 provided therein, as described in further detail hereinafter. It is apparent that by this arrangement the pump 35 is operative to discharge a stream of washing or rinsing water into the water spraying assembly 40 under a substantial pressure.

In accordance with this invention, this improved water spraying assembly 40 comprises a lower stationary section 50, connected to the pump 35 as hereinbefore described, and a vertically aligned rotatable upper section 60 which is in communication with the stationary section 50 through a rotation joint 70. As shown in the drawings, the upper section 60 is rotatably joined to the lower section 50 by a stud shaft 55, and both upper and lower sections are generally tubular so that together they define a fluid conduit which directs the flow of water from the pump to the washing chamber 12 for spraying on the dishes or other articles to be washed.

In this embodiment, the stationary section 50 of the spraying assembly comprises a vertical conduit pipe 51 secured below the bottom member 2t) and including inlet opening 52 for connecting the pump 35 to the spraying assembly. In addition, section includes an annular shoulder 53 on its top end, shown in the view of FIG- URE 4, wherein the lower and upper sections 50 and 60 of this spraying assembly 40 are separated by more than the desired gap for clarity of illustration. This shoulder 53 may extend a smal] distance into the washing chamber 12 through a corresponding opening 31 in the bottom member 20, and defines a restricted circular orifice 54 of predetermined diameter which provides the lower part of the rotation joint 70, as described further hereinafter. If desired, a suitable gasket 56 may be positioned between the shoulder 53 and the bottom member 20 to prevent water leakage through the opening 31.

Pipe conduit 51 also includes perforated stud washers 57 and 58 which support the lower end of stud shaft 55 but allow the wash or rinse water to flow freely in both upward and downward directions within the pipe. This free downward flow of water through pipe 51 permits the fluid conduit 59, connected between the lower end of the pipe 51 and the strainer assembly 25, as seen in FIGURE 1, to direct fluid from pump 35 to the strainer for operating the strainer spray arm 27 to clean the filter screen in the manner described in the hereinabove mentioned Patent 3,090,391.

The upper section 60 of this water spraying assembly 40 in accordance with this invention is positioned within the washing chamber 12 in vertical alignment with the lower pipe 51. As seen in FIGURES 1 and 3, section 60 in this embodiment comprises a hollow center tube 61 having hollow spray arms 62 extending transversely therefrom. These spray arms 62 include reaction jets 63 through which wash and rinse water may be sprayed into the compartment 12 and are in communication with the interior of tube 61 through the openings 64. These jets 63 are also positioned on arms 62 so that the force of the fluid flowing through the jets will rotate the arms within the washing chamber 12.

To mount this center tube 61 and the arms 62 for rotation about shaft with the center tube 61 in axial alignment with the pipe 51, the center tube is connected to a hub 80, such as by a screw 81, and the hub is mounted on the shaft by suitable bearing means such as the graphite sleeves 82 and retained by washer 84 and nut 83. Adjusting means associated with this hub and shaft structure may be provided for varying the vertical position of the tube 61.

FIGURE 3 illustrates that the hub 80 includes longitudinal channels 85 which allow the wash or rinse water to flow upwardly through the hub and into the arms 62 during the operation of this water spraying assembly. Channels 85 further permit the flow of fluid upwardly through the upper opening 86 positioned in the top end of center tube 61, so that the assembly will spray the water against the dishes or other articles in the chamber 12 from many different directions. A deflector S7 may be mounted on this top end of tube 61 as seen in FIG- URE l, to direct the fluid spraying from upper opening 86 downwardly onto the articles being washed.

The view of the assembly of this invention shown in FIGURE 4 clearly illustrate that the lowermost end of center tube 61 also defines a circular restricted orifice 65 of predetermined diameter which is to be positioned directly above and in closely spaced relationship with the orifice 54 provided in the lower pipe 51. The portion of center tube 61 surrounding orifice 65 therefore defines the upper part of the rotation joint 70 provided between the rotatable and stationary sections of this spraying assembly.

To permit relative rotation between center tube 61 and the stationary lower pipe 51, it is a feature of this invention to maintain a small gap at this rotation joint 70 between the restricted circular orifices 54 and 65. This small gap, for example approximately 0.016 inch, can be readily provided by adjusting the nut 83 and shim 84 to obtain the desired vertical positioning of the center tube 61 with respect to the pipe conduit 51. By this arrangement, frictional engagement between tube 61 and pipe 51 at joint 70 is precluded, thereby eliminating the frictional resistance of the joint 70 which would otherwise inhibit the free rotation of the center tube 61 within the washing chamber 12 during the operation of this improved water spraying assembly.

The improved spraying assembly 40 in accordance with this invention further includes means which tends to confine the fluid within the conduit during its passage through the gap between the closely spaced orifices 54 and 65 defining joint 70 and thus prevent the escape of any substantial amount of wash or rinse water outwardly through this joint into the washing chamber 12, without creating any substantial frictional resistance at joint 70. By this invention, therefore, the gap may be considered for purposes of definition as being substantially or effectively sealed. It is therefore a feature of this invention to limit the flow of fluid outwardly through joint by reducing the pressure of the fiuid flowing through the joint until the internal pressure within the joint is substantially equal to the pressure of the medium in the washing chamber 12 surrounding the joint.

To accomplish this internal pressure reduction and to thus substantially prevent leakage from joint 70, FIG- URE 4 shows that the diameter of restricted orifice 54 is made substantially smaller than the main internal diameter of the lower pipe conduit 51, and the upper end 51 of pipe 51, adajacent the center tube 61, is tapered inwardly to define a frusto-conical internal configuration. Upper end 51 of the pipe 51 and the orifice 54 thereby provide a converging nozzle 71 immediately below joint 70 through which fiuid from pump 35 will flow to the joint during the operation of the dishwasher.

In addition, FIGURE 4 illustrates that the diameter of restricted orifice 65 is made substantially smaller than the main internal diameter of the center tube 61, and the lower end 61 of tube 61, adjacent the pipe conduit 51, is tapered inwardly to also define a frusto-conical internal configuration. The lower end 61 of tube 61 therefore provides a diverging nozzle 72 immediately above joint 70 which receives the fluid flowing through the joint. The predetermined diameters of restricted orifices 54 and 65 are substantially the same size, or the orifice 65 may be slightly larger, to insure that fluid flowing through joint 70 may readily flow into this diverging nozzle 72 without leaking outwardly through the joint.

From the above description, it is apparent that the adjacent converging nozzle 71 and diverging nozzle 72 of this spraying assembly and the closely spaced restricted circular orifices 54 and 65 define a split Venturi tube with the throat portion thereof having a transverse gap positioned at the location of the joint 70 to be effectively sealed. The tendency of the water to leak out through joint 70 is thus greatly minimized due to the reduction of the fluid pressure within the joint induced by the flow of fluid through this Venturi throat.

In the operation of the spraying assembly of this invention, fresh 0r recirculated water is forced into the lower pipe conduit 51 through inlet opening 52 under the desired pressure by the pump 35 and is directed upwardly into center tube 61. As this water flows upwardly through the converging nozzle 71, the tapered configuration of the nozzle increases the velocity of ow to a maximum velocity at the joint defined by the closely spaced restricted orifices 54 and 65. A substantial decrease in pressure of the fiuid within joint 70 attends this increase in flow velocity induced by converging nozzle 71. As the fluid continues to fiow through the joint 70 into the orifice 65, the diverging nozzle 72 reduces the flow velocity and induces an increase in the fluid pressure so that the fluid will flow upwardly under normal pressure into the center tube 61 and the spraying arms 62. A portion of this flow will then be discharged onto the dishes within chamber 12 through the top opening 86 in the center tube, and the remainder of the fiow will spray on the dishes through the reaction jets 63 provided in the spraying arms. As discussed hereinabove, the pressure of the flow through jets 63 causes a reaction force which rotates the arms 62 and center tube 61 within the washing chamber 12 about the shaft 55.

The location of joint 70 at the throat of this Venturi tube in the above-described manner therefore minimizes the pressure differential between the internal portion of the joint and the substantially atmospheric medium of the wash chamber 12 surrounding the joint, which would otherwise cause the loss of a substantial amount of washing or rinsing water outwardly through the gap at joint 70 during the spraying operation. The fluid sealing of joint 70 is thus affected in a manner which does not create frictional resistance to the rotation of the upper section 60 of the spraying assembly with respect to the lower stationary section 50. Of course, if the external medium surrounding the joint 79 is varied, the Venturi tube size, fluid inlet and outlet pressure, and size of the gap at the Venturi throat may also be varied to accomplish the desired pressure equalization.

It should be understood that the foregoing is merely illustrative of an embodiment of this invention. Various modifications in the structural and functional features of this improved dishwasher spraying assembly may be devised by those skilled in the art without departing from the scope of this invention, as set forth in the accompanying claims.

I claim:

1. In a dishwasher spraying assembly including a conduit having communicating stationary and rotatable sec-1 tions for directing a flow of fluid from a circulation pump to the wash chamber of the dishwasher, the improvement comprising a split Venturi tube connecting the adjacent ends of said sections and having converging and diverging portions closely spaced apart by a transverse gap at the throat portion of said Venturi tube to effect an increased fluid velocity and a decreased fluid pressure at said transverse gap and to thereby define a circular substantially friction-free and leakage-free joint between said rotatable and stationary sections of said conduit.

2. In a spraying assembly for discharging a spray of washing fiuid from a circulation pump into the wash chamber of a dishwasher, the combination comprising a conduit including means to connect said conduit to said circulation pump, a center tube including means for discharging a spray of washing fluid into said washing charnber, means to rotatably mount said center tube in coaxial alignment above said conduit, and means joining the adjacent ends of said conduit and said center tube in substantially leakage-free fiuid communication comprising a split Venturi tube extending between said adjacent ends and hai-ing converging and diverging portions closely spaced apart by a transverse gap at the throat portion of said Venturi tube for defining a circular closely spaced joint of predetermined diameter between said conduit and said center tube whereby said joint permits the free rotation of said center tube with respect to said conduit and whereby said Venturi tube substantially seals said joint by increasing the fluid velocity through said joint for reducing the fluid pressure within said joint to a pressure substantially equal to the pressure of the medium surrounding the joint.

3. In a spraying assembly for discharging a spray of washing fluid from a circulation pump into the wash chamber of a dishwasher, the combination comprising a non-rotatable conduit including a converging nozzle on one end thereof for receiving a flow of fluid discharging from a dishwasher circulation pump, means to connect said conduit to said circulation pump, a center tube including a diverging nozzle on one end thereof and further including means for discharging a spray of washing fiuid into said wash chamber, and means rotatably mounting said center tube in coaxial alignment adjacent said conduit with said converging and diverging nozzles defining opposed circular restricted orifices positioned in closely spaced facing relationship to provide a closely spaced circular joint between said conduit and said center tube, whereby said joint joins said non-rotatable conduit and said rotatable tube in fluid communication while permitting freerotation of said center tube with respect to said conduit and whereby said opposing nozzles substantially seal said joint by increasing the fiuid velocity through said joint for reducing the uid pressure within said joint to a pressure substantially equal to the pressure of the medium surrounding the joint.

4. The invention according to claim 3 wherein said tube includes spray arms extendable within said chamber and having fluid reaction jets thereon for rotating said arms and discharging a spray of said fluid into said chamber.

5. The invention according to claim 3 wherein said means rotatably mounting said center tube adjacent said conduit comprises a stud shaft extending axially within said conduit through said restricted orifices and having the opposite ends thereof connected to said conduit and to said center tube.

6. In a spray assembly for discharging a spray of washing fluid from a circulation pump into the wash chamber of a dishwasher, the combination comprising a non-rotatable conduit including a converging nozzle on one end thereof for receiving a ow of fluid discharging from a dishwasher circulation pump, means to connect said conduit to said circulation pump, a center tube including a diverging nozzle on one end thereof and further including transversely extending spray arms having reaction jets thereon for rotating said arms and discharging a spray of said fluid into said wash chamber, and a stud shaft extending axially within said conduit through said converging and diverging nozzles and connected to said conduit and said center tube to rotatably mount said center tube in coaxial alignment adjacent said conduit with said converging and diverging nozl"zles defining relatively rotatable opposed circular restricted orifices positioned in closely spaced facing relationship to provide a closely spaced circular joint between said conduit and said center tube joining said conduit and said tube in substantially leakage-free fluid communication and permitting free rotation of said center tube with respect to said conduit, whereby said opposing nozzles seal said joint by increasing the fluid velocity through said joint for reducing the fiuid pressure within said joint to a pressure substantially equal to the pressure of the medium surrounding the joint.

7. In a dishwasher having a wash chamber for receiving the articles to be washed and further having a pump to circulate washing fluid through the chamber, a spraying assembly for directing the flow of fluid from said pump to said chamber, said assembly comprising a fluid conduit having a stationary section connected to said pump to receive a flow of fluid discharging from said pump and to conduct said fluid through said conduit, said conduit further having a rotatable section extending wherein said wash chamber and including means for introducing a spray of said fluid into said chamber, means rotatably mounting said rotatable section of said conduit to said dishwasher in alignment with said stationary section, and means joining said rotatable and stationary sections of said conduit in Substantially leakagefree fluid communication comprising a split Venturi tube connected to and extending between adjacent ends of said sections and having converging and diverging portions closely spaced apart by a transverse gap at the throat portion of said Venturi tube for defining a circular closely spaced joint of predetermined diameter between said sections, whereby said joint permits the free rotation of said rotatable section of said conduit with respect to said stationary section and whereby said Venturi tube substantially seals said joint and prevents the loss of tluid outwardly therethrough by increasing the fluid velocity through said joint for reducing the fluid pressure within said joint to a pressure substantially equal to the pressure of the medium surrounding the joint.

8. In a dishwasher having a wash chamber for receiving the articles to be washed and further having a pump to circulate washing fluid through the chamber, a spraying assembly for directing the flow of fluid from said pump to said chamber, said assembly comprising a lluid conduit having a stationary section connected to said pump to receive a flow of iluid discharging from said pump and to conduct said fluid through said conduit, said conduit further having a rotatable section extending with in said wash chamber and including means for introducing a spray of said tluid into said chamber, means rotatably mounting said rotatable section of said conduit to said dishwasher in alignment with said stationary section, and means joining the adjacent ends of said rotatable and stationary sections of said conduit in substantially leakage-free uid communication comprising a converging nozzle joined to said adjacent end of said stationary section to constrict the fluid owing within said stationary section and a diverging nozzle jointed to said adjacent end of said rotatable section for rotation therewith and for receiving the fluid flowing from said converging nozzle with said converging and diverging nozzles defining closely spaced and axially aligned circular restricted orifices of predetermined diameter providing a closely spaced joint between said sections of said conduit, whereby said joint permits the free rotation of said rotatable section of said conduit with respect to said stationary section and whereby said nozzles substantially seal said joint and prevent the loss of fluid outwardly therethrough by increasing the fluid velocity through said joint for reducing the fluid pressure within said joint to a pressure substantially equal to 'the pressure of the medium surrounding the joint.

9. In a dishwasher having a wash chamber for receiving the articles to be washed and further having a pump to circulate washing fluid through the chamber, a spraying assembly for directing the flow of fluid from said pump to said chamber, said assembly comprising a stationary conduit connected to said pump to receive a flow of tluid discharging from said pump and to conduct said fluid through said stationary conduit, a rotatable center tube extending within said wash chamber and including transverse spray arms in communication with said center tube, said spray arms including reaction jets to rotate said arms and discharge a spray of said fluid into said chamber, a stud shaft having one end connected within said stationary conduit and the other end connected within said center tube to rotatably mount said center tube in coaxial alignment with said stationary conduit, and means joining the adjacent ends of said stationary conduit and said center tube in substantially leakagefree fluid communication comprising a converging nozzle joined to one end of said stationary conduit to constrict the iluid flowing within said conduit and a diverging nozzle joined to one end of said center tube for rotation therewith and for receiving the fluid flowing from said converging nozzle with said converging and diverging nozzles defining closely spaced and axially aligned circular restricted orifices of predetermined diameter providing a closely spaced joint between said conduit and said center tube, whereby said joint permits the free rotation of said center tube and said spray arms with respect to said stationary conduit and whereby said nozzles substantially seal said joint to prevent the loss of fluid outwardly therethrough by increasing the fluid velocity through said joint for reducing the fluid pressure with-` in said joint to a pressure substantially equal to the pressure of the medium surrounding the joint.

References Cited UNITED STATES PATENTS 3,009,470 11/1961 Zurek 239--261 X 3,009,716 11/1961 Bradfute et al. 285-133 X M. HENSON WOOD, JR., Primary Examiner.

V. M. WIGMAN, Assistant Examiner. 

